DE2514230A1 - SYSTEM FOR EXPOSURE MEASUREMENT AND / OR FOR FOCUS DETERMINATION WITH THE HELP OF AN IMAGE SENSOR - Google Patents

Description

T.EDTKE - BüHL.NG - K.NNE

Dipl.-Chem. Bühling Dipl.-Ing. Chins

8 Munich 2, P.O. Box 202403 Bavarlarlng 4

2 5 1 4 2 3 0 Tel .: (0 89) 53 96 53 Telex: 5 24845 tipat cable: Germaniapatent Munich April 1st, 1975

ti 65 ^ 7

Canon Kabushiki Kaisha Tokyo, Japan

System for exposure measurement and / or for determining the focus with the help of a Image sensor

The invention relates to a system for measuring exposure for an optical device such as, for example a camera and / or for determining the focus for the imaging optics.

Among the conventional light metering systems for optical devices such as cameras in which the light metering method suitable for the captured image field at the time of image capture can be selected, there is one which is constructed so that a plurality of light sensor elements such as CdS cells for point light metering and a other plurality of light sensor elements such as CdS cells for the through vi / 8 509841/090 *

Dtuttch · Bank (Munich) Account 51 / »1070 Draidntr Bank (Munich) Account 3939144 Postscheck (Munich) Account 670-43-804

Sectional light measurement are provided at mutually different points, with the image recording in accordance with the nature of the image recording field the image acquisition either the point light measurement or the average light measurement by comparing the output signal one light metering method is selected with that of the other light metering method so as to carry out the appropriate exposure metering.

An example of this is in US Patent 3 690 2 ¹ H disclosed camera in which a first light sensor element is arranged so that it is brought against the film, while a second light sensor element is arranged so that the surface of a viewfinder optical system the camera-forming pentagonal prism through which the light beam exits the pentagonal prism, the first light sensor element for the so-called point light measurement, which responds to a relatively small part of the light beam to be exposed, while the second light sensor element is used for the on ^! The so-called average light measurement is used for almost the entire light beam coming from the image recording field. The first and the second light sensor element can optionally be connected to the same exposure measuring circuit by means of a manual operation on the outside of the camera select either the point light measurement or the average light measurement in order to

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wise connecting the first or the second light sensor element to the exposure metering circuit and through, for example using a meter to compare the output signal in the one light measurement method with that in the other light metering method to carry out a suitable exposure measurement.

In the case of the light metering system constructed as explained above, however, the light sensor element is for the point light measurement arranged in a certain fixed position with respect to the image plane, so that it is disadvantageous that the light beam only at a certain fixed point of the object on the image plane can be measured, with a limitation, for example, in the case of a single-lens reflex camera consists in that the area for point light measurement is determined in advance because the point light measurement is not at any arbitrary optical position of the object can be carried out in the image plane in the viewfinder.

On the other hand, various methods and devices for determining the focus of the Proposed imaging optics utilizing the photoelectric properties of the photoelectric conversion elements, where as a theoretical possibility of maintaining the focus with relatively great accuracy by Japanese Patent Publication No. Sho ^ 2-11109 proposed method is considered, according to which a

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A plurality of parts with a small but precise area is provided on the focal plane, so that by converting the amount of light at each small part by means of the photoelectric conversion element, the electrical output signal is obtained in the manner v * ird _s ds. ¹ -: the differences in the electrical output signals between two adjacent small parts are converted into absolute values or squared values and then added, it being assumed that the focus has been reached when the added value assumes a maximum.

In the case of the in Japanese Patent Publication No. Sho ^ 2-14096, however, the analog amount of the Output signal of each photoelectric conversion element is processed, thereby building up the signal processing circuit for processing the output of each photoelectric conversion element is very complicated, so that the exact determination is practically impossible because of the errors occurring when processing the output signals, which is a Represents power. It is also in accordance with the increase in the number of photoelectric conversion elements the structure of the circuit is many times more complicated, so that the number of elements used necessarily is limited.

Further, one has hitherto been disclosed, for example, in Japanese Utility Model Publication No. Sho 48- ^ 3379 disclosed device for focus determination and exposure measurement is known in which a light sensor device

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device with a variety of small light sensor elements is used, in the case of the Japanese Utility Model Publication No. Sho 48-43379 Device with regard to the analog control, a method is used according to which to control the focus detection and Light measuring device, the analog amount of the output signal of each light sensor element of the light sensor device is processed. In the analog control, however, there is a theoretical instability such that in the case of the Use of a single light sensor device for the focus determination and for the exposure measurement of the structure of the electrical circuit becomes complicated, with the error at the time of focus detection and exposure measurement becomes larger, so that an accurate measurement is practically impossible. If the light sensor system is made up of a plurality composed of light sensor elements is made in accordance with the increase in the number of light sensor elements the structure of the circuit is many times more complicated, so that necessarily the number of light sensor elements is limited, which makes accurate measurement even more difficult.

The object of the invention is to provide a system for exposure measurement and / or for determining the focus To create imaging optics, with the help of which all the above-mentioned disadvantages of the conventional exposure metering system, the conventional focus detection system and the system using a single light sensor device

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direction for exposure metering and focus determination be eliminated.

According to the invention, a new system for exposure measurement and / or for determining the focus of the image imaging optics is provided created, with the help of which all the above-mentioned disadvantages of the conventional light metering system, the conventional Focus detection system and a single light sensor device for exposure measurement and the system using the focus detection is thereby eliminated can be that by means of a plurality of arranged or integrated small light sensor elements containing Image sensor, the image pattern of the object is scanned in a purely electrical manner and the output signals obtained thereafter the light sensor elements are implemented.

The system according to the invention is also intended to provide an exposure metering system for automatically selecting a for the nature of the image pickup field can be created suitable light measuring method.

The system according to the invention provides that by means of of the image sensor any arbitrary fine proportion of the brightness on the entire image area of the image pickup field optionally can be measured.

According to a particular embodiment of the system according to the invention, the exposure metering system is designed in such a way that

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that by means of the image sensor the point light measurement at any arbitrary small portion of the brightness on the overall image area of the image recording field can be carried out while the average light measurement for the entire image area of the image recording field can be carried out, so that automatically with the aid of the output signals of the two light measuring systems any of the light metering systems can be selected.

The exposure measuring system of the system according to the invention is advantageously constructed in such a way that with the aid the light sensor device which is arranged to receive the light beam coming from the object to be recorded, and those for forming the image sensor, such as a photodiode array (MOS image sensor), of charge-coupled devices Devices (charge coupled devices, CCD) and the like. Has a plurality of small light sensor elements, an output signal in each of the small light sensor elements of the light sensor device by scanning the image pattern of the object is generated, which corresponds to the position of the object to be recorded, and that by optionally removing the Output signal for the object to be recorded a desired one. Point light measurement can be carried out.

The invention further provides a focus detection system which is constructed so that in the image formation position the imaging optics or an image sensor in the position equivalent to the image formation position from a plurality of finely structured or integrated

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Light sensor elements is arranged and that the output signals of the light sensor elements in the image sensor one after the other can be converted into digital values in accordance with the arrangement order, while the absolute values of the differences between the digital values of the output signals more contiguous Light sensor elements are added up one after the other ", whereby the fine adjustment is considered to have been achieved, when the total sum of the absolute values of the differences between the digital values during the setting of the Image education optics becomes largest. &

The system according to the invention is used to build the Camera with automatic focusing of the image pickup optics by equipping an existing camera with a Focus detection system which is so constructed that by means of an image sensor with a plurality of small Light sensor elements scanned the image pattern of the object imaged by means of the optics in a purely electrical manner and the scanning signals obtained in this way are successively converted into digital values, while the absolute values of the Differences between the digital values for neighboring light sensor elements are summed up one after the other, with the Focusing of the optics determined by determining the change in the summed value during the adjustment of the optics will.

With the invention, a system for exposure measurement and for focusing determination by means of a common

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seeds created light sensor device constructed in such a way is that the combined signal, i.e. both the in-focus signal as well as the exposure signal is obtained in that a plurality of finely divided or Integrated light sensor elements having image sensor, the image of the object is scanned and each is obtained Output signal of each light sensor element is successively converted into a digital value.

The invention is explained below on the basis of the description of exemplary embodiments with reference to the drawing explained in more detail.

Pig. 1 shows an embodiment of the arrangement of FIG Light sensor elements which are suitable for the exposure metering system according to the invention.

Pig, FIG. 2 shows a block diagram of an embodiment of the exposure measuring system according to the invention using the Pig. I illustrated image sensor IS for use in a common camera.

Fig. 3 (a) shows an electrical diagram of the

electrical connections between the photodiode array, the analog switch 1 and the shift register 2 when using the photodiode array (MOS image sensor) as

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Image sensor IS in the case of the embodiment shown in FIG.

Fig. 3 (b) shows the timing chart for illustration in the electric circuit shown in Fig. 3 (a) pass the photodiodes one by one extracted output signals.

Fig. 4 shows the most essential parts of a camera in which an exposure metering system according to the Representation in Fig. 2 is incorporated.

Fig. 5 (a) shows an embodiment of the arrangement of the Light sensor elements of the image sensor that are used for the focus detection system according to the invention suitable is.

FIG. 5 (b) shows a portion of the image sensor IS ¹ shown in FIG. 5 (a) on an enlarged scale.

Fig. 6 (a) shows a basic arrangement of the most essential parts in the application .des according to the invention Focus detection system in an ordinary camera.

Fig. 6 (b) shows the relationship between the light sensor area of the image sensor IS 'and the

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Image plane of the object in the arrangement shown in Fig. 6 (a).

Fig. 7 shows the electrical block diagram of an embodiment of an ordinary camera in which the focus detection system according to the invention using the image sensor IS ¹ shown in Fig. 5 (a) and (b) is used.

Fig. 8 is a diagram showing the change of the value calculated by means of the integrating circuit 109 as a function of the adjustment of the image recording optics L during the operation of the focus detection system shown in FIG.

Fig. 9 shows the structure of the essential parts of a motion picture camera in which a focus detection system is installed as shown in FIG.

Fig. 10 shows an electrical block diagram of an embodiment of a conventional camera, in which a system according to the invention for exposure measurement and for determining the focus with the help of a common image sensor is used.

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Pig. 11 shows a structure of the main parts of the camera into which a system according to FIG Representation in Fig. 10 is incorporated.

In Figs. 1 to ¹ I, the embodiments of the Belichtungsmeßsystems with application of the image sensor are illustrated, while in Figures 5 to 9, the illustrated embodiments of the focus detection system with application of the image sensor. the embodiments of the system for exposure measurement and for focus determination using a common image sensor are shown in FIGS.

First, an embodiment of an ordinary camera will be described with reference to FIGS. 1 to 4, in which the exposure metering system is used with the help of the image sensor.

Fig. 1 shows an embodiment of the arrangement of a Large number of small light sensor elements in an image sensor IS such as a photodiode array (MOS image sensor) / at charge coupled devices (CCD) and the like, wherein each of the small light sensor elements is mounted in a position that a small portion of the image area of the object to be photographed on the Manner corresponds to that the brightness at each of the small portions of the object in correspondence with each of the light sensor elements can be determined.

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This image sensor IS is installed in place of the light metering element for exposure measurement in the ordinary camera; as the mounting position for the image sensor, in the case of the internal light metering system (the so-called TTL light metering system in which the light beam coming from the image pickup field through the image pickup lens is measured), the vicinity of the position equivalent to the image formation plane of the pickup lens is suitable, while in the case of a conventional one single-lens reflex camera, the optical image search path is suitable, wherein the exposure measuring system according to the invention is preferably to be mounted in a position in which the light can be measured over the entire area of the image recording field; Here, as shown in FIG. H, a reflecting surface of the pentagonal prism forming part of the viewfinder optics is made semitransparent and the exposure metering system is glued to the semitransparent surface or attached close to the semitransparent surface.

In the image sensor IS shown in Fig. 1, the light sensor ^{elements are denoted by I 1} to n ¹ , while Z ₁ - represents the point area for carrying out a point light measurement in the central part of the image plane of the object to be recorded, the point light measurement using the point area Z ₁ located light sensor elements n ¹ - k ¹ to n ^{1 is} performed; Z2 represents the point area for carrying out a point light measurement on the upper left part of the image plane of the object to be recorded, the point light-

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measurement is carried out with the aid of the light sensor elements 1 'to n' - a 'located in this point area Zp. Z- is the point area for performing a point light measurement on the upper right part of the image plane of the object to be recorded, the point light measurement being carried out by means of the light sensor ^{elements n 1} - b ¹ to n ¹ - c ¹ located in this point area Z -. Z ^ represents the point area for performing a point light measurement on the lower right part of the image plane of the object to be recorded, the point light measurement using the point area Z ₁ . lying light sensor elements n '- d ^f to n ¹ - e ^{1 is} executed. Zr is the point region for carrying a point light measurement on the lower left part of the image plane of the object to be recorded, wherein the point light measurement using situated in this point range Zr light sensor elements n ¹ f · to n ¹ - g is performed. ¹

FIG. 2 shows an electrical block diagram of an embodiment of the exposure system using the image sensor IS shown in FIG. 1; In FIG. 2, 1 'to n ¹ denote the light sensor elements shown in FIG. 1, which are connected in series with an analog switch 1 for successively transmitting the output signals of the light sensor elements 1' to n 'to an arithmetic amplifier 7 in the next construction stage are connected, the analog switch 1 is connected to a shift register 2. The shift register 2 is connected to a gate control circuit 3, which is controlled by means of the control signal from a read-only memory (ROM) 5.

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will be. The gate control circuit 3 is constructed in such a way that a gate circuit 17 is controlled with the aid of the signal from the read-only memory 5. A diode 6, together with the computing amplifier 7, forms a logarithmic compression circuit A. A clock pulse generator 10 for generating reference pulses by means of the signal from the read-only memory 5 is connected to a digital-to-analog converter 9, at the output terminal of which a stepped output signal is generated, as shown in FIG is represented by 9q in the drawing. 8 is a comparison circuit whose input terminals are connected to the arithmetic amplifier 7 and the digital-to-analog converter so that the output signals of these two circuits are compared with one another. A gate circuit 11 connects the comparison circuit 8 to the clock pulse generator 10 and has, for example, a conventional NAND circuit or the like. A counter 12 is controlled with the aid of the read-only memory 5 and, together with the clock pulse generator 10, the digital-to-analog converter 9, the comparison circuit 8 and the gate circuit 11, forms an analog-to-digital converter. 13 is an adding circuit whose input terminals are connected to the output terminal of the counter 12 and the feedback line; a register 14 controlled by means of the read-only memory 5 are connected in the next stage. The gate circuit 17 is constructed so that according to the selected position of a read-only memory selector switch k, for example in the case of the selection of the point area Z ^, the content of the counter 12 is transmitted by means of the signal from the gate control circuit 3 to the adder circuit 18 if

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the light sensor element n ¹ - k 'comes its turn or is queried. A register 19 is controlled by means of the test value memory 5 and fed back to the adding circuit 18, for example in the case of selecting the point area Z ^ the value of the light measurement of each light sensor element after the element n ¹ - k ^{f is} added one after the other. A division circuit 20 is controlled by the read-only memory 5 in such a way that the content of the register 19 is determined by the total number of light sensor elements in the respective dot area, namely in the case of the selection of the dot area Z .. by the total number (in this case k ¹ +1 ) the light sensor elements is divided by the element n '- k ^1. A register 21 is connected to the division circuit 20 to store the value obtained therefrom. The gate circuit 17, the adding circuit 18, the register 19 *, the dividing circuit 20 and the register 21 form the point light measuring system C.

A division circuit 15 is controlled by means of the read-only memory 5 in such a way that the content of the register 14 is divided by the total number (n ¹ ) of the light sensor elements. A register 16 is connected to the division circuit 15 to store the value obtained therefrom. The adding circuit 13 »the register I ¹ I, the division circuit 15 and the register 16 form the average light measuring system D.

A comparison circuit 22 is connected to the two registers 16 and 21 in such a way that in the case of one

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Simultaneous selection of a control content Ra and another content R ^ to R ₁ - the content of the register 16 is compared with the content of the register 21 by means of the read-only memory selector switch 4, gate circuits 23 and 24 being connected in such a way that the gate circuit 24 is switched on when the contents of the two registers show a difference in exposure of more than -2Ev, while the gate circuit 23 is switched on when the contents of the two registers show a difference in exposure of less than -2Ev. A computing circuit 25 is connected to the output terminals of the gate circuits 23 and 24 in such a way that the information signal about the light measurement from the gate circuit 23 or the gate circuit 24 together with the logarithmically compressed digital signal about the exposure factors such as the shutter speed value 28, the aperture value 27, the ASA A sensitivity value 26 and the like is processed to thereby control an aperture control device 30 or a shutter time control device 29 connected to the arithmetic circuit 25; The computing circuit 25 is also connected to a buffer memory 31 controlled by means of the read-only memory 5, so that the exposure information suitable for the subsequent image recording is displayed by means of the display device E which, in addition to the buffer memory 31, also has a decoder 32 and a display part 33 .

A changeover switch 35 is used to switch between the aperture control device 30 and the shutter speed control device.

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direction 29 »while a switch 34 to switch between the shutter speed value 28 and the aperture value 27 are used.

The read-only memory selector switch ¹ J is a selector switch for selecting the control memory values or control memory contents set in the read-only memory 5. R is one of the set in the read only memory 5 the control memory contents, wherein R ₁ should be turning, the gate circuit 17, while located in the dot region Z ₁ light sensor elements n ¹ - k ¹ n ¹ output signals generate, so that the PunktIichtmessüng performed in the dot region Z ₁ will. The control memory content Rp set in the read-only memory 5 is intended to switch on the gate circuit 17 during the output signal generation by the light sensor ^{elements I 1} to n ¹ - a ¹ _{located in the point area Z 2} »in order to carry out the point light measurement in the point area Zp. A control memory content R stored in the read-only memory 5 is intended to put the gate circuit 17 into the switched-on state, while the light sensor elements n ¹ - b ¹ to n ¹ - c ^{1 located in the} point area Z shown in FIG. 1 generate output signals so that the point light measurement in the point area Z, is performed. A control memory content R ^ of the ROM 5 is intended while the output signal generating in the item area Z ^ of Figure 1 located light sensor elements n. ¹ - d ¹ to n ¹ - e ', the gate circuit 17 turn on, so as to perform spot light measurement in the point region Z ₁ J . A control memory content R ₁ - of the read-only memory is used to switch on the gate circuit 17 during the output

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signal generation in the item area Z ₁ - light sensor elements located ^n! - f "to n ¹ - g 'for carrying out the point light measurement in the point area Zf-. The control memory contents R ₁ to R [- have one thing in common in that when one of the control contents R ^ to R is selected, - by means of the plague memory selector switch k the comparison circuit 22 and the gate circuit 23 are inoperative while the gate circuit 2k is in operation.

R. is one of the control memory contents, the sole selection of which by means of the Pest memory selector switch H, the comparison circuit 22 and the gate circuit 2h are out of operation, while the gate circuit 23 is in operation. If the control memory contents R. and one of the control _{memory contents R 1} to Rc are selected at the same time by means of the Pest memory selector switch H , the comparison circuit 22 is in operation, while the gate circuits 23 and 24 are controlled by means of the control signals from the comparison circuit 22.

The following will be the control procedure on the timing the successive extraction of output signals of the photodiodes in the specific case of using a photodiode array (MOS image sensor) as the image sensor IS.

Fig. 3 (a) is an electrical diagram of the electrical connections between the photodiode array, the analog switch 1 and the shift register 2 in the case

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the use of a photodiode array as an image sensor, while the Pig. 3 (b) is the timing diagram for illustration of the output signals sequentially extracted from the photodiodes in the electric circuit shown in Fig. 3 (a) represents.

If in the circuit according to FIG. 3 (a) when the clock pulses ^ ₁ 'and φ ₂ ' shown in FIG. 3 (b) are applied to the clock connections φ. und0 ₂ ^{the start pulse Vs 1} shown in Fig. 3 (b) is applied to the start pulse input terminal Vs, a voltage shown at VG 'in Fig. 3 (b) is applied to the gate VG _{1 of} the first switch S _{1 of} the analog switch 1 to the Applied in such a way that the photodiode D ₁ generates an output signal corresponding to the light in the image pickup field. After half a period of the clock pulses φ ^ 'and φ ₂ ', a _{voltage shown at VG 2} '^ ⁿ ^ S * 3 (b) is applied to the gate VGp of the second switch S "of the analog switch 1 in such a way that the photodiode D _{2 turns on} generates an output signal corresponding to the light in the image pickup field. After another half cycle of the clock pulses Φ ₁ 'υηαφ _{2 ', the voltage VG 1} ¹ applied to the gate VG ^ of the first switch S is reset in order _{to open the switch S 1} and to close the switch of the next stage in such a way that the photodiode connected to the switch of the next stage generates an output signal. During the repetition of the above-mentioned functional processes, the photodiodes of the photodiode array successively generate the output signals.

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The operation of the light metering system will now be explained with reference to Figs.

If now by closing a power supply switch, not shown in the drawing, the system is in operation is taken, while by means of the read-only memory selector switch 4, the control memory contents FL and R. simultaneously are selected, by means of the signal from the read-only memory 5, the shift register 2 and the gate control circuit put into operation in such a way that the output signal of the first light sensor element 1 'of the image sensor IS over the analog switch 1 to the logarithmic compression circuit consisting of the computing amplifier 7 and the diode 6 A and further after its logarithmic compression in the logarithmic compression circuit A to the comparison circuit 8 is transmitted. On the other hand, the clock pulse generator 10 generates by means of the read-only memory 5 Clock pulses sent to the digital-to-analog converter 9 and at the same time are transmitted via the gate circuit 11 to the counter 12 so that they are counted in the counter 12.

The digital-to-analog converter 9 generates a staircase signal 9q according to the number of clock pulses, the logarithmically compressed signal of the light sensor element I ^{1 being} compared with the staircase _{signal 9 0} in such a way that if the two signals are equal, the comparison circuit 8 generates a switch-off signal. The switch-off signal is fed to the gate circuit 11 to switch it off, whereby the

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Forwarding of the clock pulses to the counter 12 is blocked, the ^{digital signal corresponding to the output signal of the light sensor element I 1} having been counted by means of the counter 12.

When the counter 12 has finished counting, the control signal of the Pestwertspeicher 5 is used as Count value counted by means of the counter 12 digital signal through the adding circuit 13 in the register 14 in the average light measuring system D to be saved there.

When the register 14 has stored the digital signal, a control signal is sent to the gate control circuit 3 by means of the read-only memory 5, whereby the output signal of the light sensor element 2 'is processed in the same way as the output signal of the light sensor element I ¹ , so that it is counted and then by means of the Adding circuit 13 is added to the digital signal stored in register 14 corresponding to the output signal of light element 1 'in such a way that the sum of the output signals of light sensor elements l ^l and 2 ^! corresponding digital signals is stored in the register 14.

^{In this way, the output signals of the further light sensor elements 3 f} to n 'corresponding to the nature of the image recording field are added one after the other as digital signals in the register 14 so that they are stored therein in such a way that the total sum of the output signals in the register 14

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Signals of all light sensor elements 1 'to n ^{1 of} the in Pig. 1 shown image sensor IS corresponding digital signals is stored. As shown in FIG. 1, the light sensor elements are arranged over the entire image plane, so that a value is stored in the register I ^ which is η 'times greater than the average measured light value.

If, as described above, the total sum of the digital signals corresponding to the output signals of the light sensor elements 1 'to n' has been stored in the register IU, the total sum of the digital signals is transmitted to the division circuit 15 by means of the read-only memory 5 so that they can be determined by the number (n ^f ) of all light sensor elements is divided and stored in the register 16 as the average light measurement value.

If the output signal of the light sensor element n ¹ - k ^{1 is} processed during the light measuring process, the control signal is sent from the read-only memory 5 via the gate control circuit 3 to the gate circuit 17 in order to open it, whereby the digital signal counted in the counter 12 of the output signal of the Light sensor element n ¹ - k ^{1 is} fed to the average light measuring system D and at the same time to the adding circuit 18 of the point light measuring system C in such a way that the total sum of the output signals of the light sensor elements n ¹ - k 'to n ¹ corresponding to the mode of operation of the average light measuring system D in the register 19 Digital signals is stored. If the overall

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sum of the digital signals corresponding to the output signals of the light sensor elements n ¹ - k ¹ to n ^{1 has} been stored in the register 19, the division circuit 20 is put into operation by means of the read-only memory 5 in such a way that the total sum of the information signals n ^r - k ¹ to n ¹ for storage in the register 21 is divided by the number of light sensor elements located in the point area Z.

According to the illustration in FIG. 1, the light sensor elements n ¹ -k 'to n' for measuring the brightness of a part are arranged in the center of the image plane in the point area Z ₁ , so that the value of the point light measurement for the sub-area in the center is stored in register 21.

The value of the point light measurement stored in the register 21 is obtained by means of a signal from the read-only memory 5 and the value of the average light measurement stored in the register 16 is supplied to the comparison circuit 22, the values being compared with one another in such a way that upon finding a difference between the For exposure values of more than −2 Ev between the two values, the switch-on signal from the comparison circuit 22 is transmitted to the gate circuit 24 so that the gate circuit 24 is switched on and the value of the point light measurement stored in the register 21 via the gate circuit 24 is transmitted to the computing circuit 25 while at a difference between the exposure values less than

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2 Ev the comparison circuit 22 emits a switch-on signal to the gate circuit 23, so that the gate circuit 23 is switched on in such a way that the value of the average light measurement stored in the register 16 is transmitted via the gate circuit 23 to the computing circuit 25. The value of the point light measurement or the average light measurement transmitted to the computing circuit 25 is logarithmically compressed and is processed together with the digital ASA sensitivity value 26 and according to the switching state of the switch 3 ¹ * with the digital shutter speed value 28 or the digital aperture value 27, so that it is processed accordingly the switching state of the functionally coupled to the switch 3 ^ changeover switch 35 selectively the aperture control device 30 or the shutter speed control device 29 is supplied as a control signal while at the same time d to display the shutter speed value or the aperture value to ^it from the buffer 31> the decoder 32 and the display part 33 existing display device E is present. In the illustration in FIG. 2, the changeover switches 3 ^ and 35 are in the switching state for controlling the aperture value.

The sequence described above corresponds to the case that the control memory contents R. and R ^ are selected by means of the read-only memory selector switch ^{1 I;} If, with regard to the nature of the image recording field, it is desired to compare the point light measurement value at the upper left part of the image plane of the object to be recorded with the average light measurement value, this can only be done by means of the fixed-

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value memory selector switch 4 the control memory contents R. and select Ro.

If, by means of the read-only memory selector switch 4 for point light measurement, only the control memory content corresponding to the desired point area such as the point area Z ^ of the image area of the object to be recorded is selected, the value of the point light measurement is _{stored in the point area Z 1} in the register 21. Since only the control memory content R ^ is selected, the comparison circuit 22 and the gate circuit 23 are put out of operation, while only the gate circuit 24 is in operation, so that the value of the point light measurement stored in the register 21 in the point area Z via the gate circuit of the arithmetic circuit 25 is transmitted, the control being carried out in the same manner as in the case of a simultaneous selection of R. and R-.

If, by means of the read-only memory selector switch 4, only the contents of the control memory are used for the sole average light measurement R. is selected, the gate circuit 17 is not switched on, the point light measuring system C, the Comparison circuit 22 and the gate circuit 24 are inoperative while the gate circuit 23 is in operation, so that because of the operation similar to that described above, the value of the average light measurement in the register 16 is stored and passed on to the computing circuit 25 via the gate circuit 23 in order to

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term control as in the case of the simultaneous selection of the control store contents R _A and R ^ to effect.

FIG. H shows the practical installation of an embodiment of the above-described light metering system in an ordinary camera. The drawing shows a conventional single-lens reflex camera, only the essential parts being shown for the sake of simplicity.

In the drawing, L. denotes conventional image recording optics denotes, while with 36 a part of the viewfinder optics of the camera representing pentagonal prism is denoted, the image sensor IS cemented to the semitransparent surface 36a of the pentagonal prism 36 or attached to it. At 37 is a conventional image pickup louvre shutter mounted in the optical image pickup path denotes whose opening diameter is controlled by means of the above-mentioned aperture control device 30, what is represented by the dashed line 30 'in the drawing will. The opening and closing part of a conventional focal plane shutter is denoted by 38, wherein the opening and closing timing by means of the shutter timing control device 29 is controlled, which is shown by the dashed line 29 'in the drawing. At 39 is a Referred to as film, while F denotes a circuit block, which contains the circuits 1 to 3 and 5 to 25 according to FIG.

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When using this camera, the switch 3 ^ and the functionally linked with this switch 3 * J Changeover switch 35 operated depending on whether the automatic control of the diaphragm (the so-called automatic diaphragm control method with shutter speed priority) or automatic shutter speed control (the so-called automatic shutter speed control method with aperture priority) is desired, and the desired light measurement with the help of the fixed value selector switch * J is determined as described above. (The state shown in the drawing corresponds to Automatic shutter speed control method with aperture priority.) Then according to the sensitivity of the to be used Film 39 determined the ASA speed value 26 while in accordance with the exposure control method of either the aperture value 27 or the shutter speed value 28 is set in advance. (For the one shown in the drawing State, the shutter speed value 28 is determined in advance because the aperture should be controlled automatically.)

If, after the above-mentioned operation, the power switch not shown in the drawing is closed, the exposure metering system is operated in the same manner as in that referred to on Fig. 1 described case, the then for the image recording field suitable exposure value, namely the shutter speed value or in the case of the automatic shutter speed control in the case of automatic aperture control, the aperture value - consequently in the state shown in the drawing

509841/0904

Aperture value - in the viewfinder of the camera by means of the display device E is displayed while either the shutter speed controller 29 or the aperture controller act in such a way that the operating speed of the focal plane shutter actuators 38 or the opening diameter the louver 37 is automatically controlled so as to perform the automatic exposure control in accordance with the then prevailing condition of the image recording field to be carried out. In the state shown in the drawing. Causes while the diaphragm control device 30 is the controller the opening diameter of the louvre diaphragm 37

In this way, it is possible by operating the conventional release button not shown in the drawing in the condition described above, an image recording with that for the prevailing conditions im Image capture field to perform appropriate exposure value *

In the exposure measuring system according to the invention, both automatic exposure control is provided in this way with shutter speed priority as well as automatic exposure control with aperture priority possible.

In particular, an image sensor is used as the light sensor device in the exposure measurement according to the invention a number of small light sensing elements such as a MOS image sensor, charge coupled device (charge coupled devices, CCD) or the like. Used, whereby by

509841/0904

Arrangement of each light sensor element of the image sensor in every small part of the image plane of the image to be recorded Object corresponding position and by purely electrical scanning of the image plane of the object to be recorded with the aid of the light sensor elements, the brightness at each part corresponding to the respective light sensor element the object to be recorded is measured; a desired light measurement is thereby achieved by converting the output signal of each light sensor element into a digital value and carried out by selective extraction of the digital signal, so that automatically the most suitable Lieht measurement is chosen, which brings some advantages with this type of light measurement, such as the possibility a point light measurement over a large area of the image plane of the object to be recorded for automatic selection the most suitable light measurement for the existing imaging conditions.

It is of course possible to design the present embodiment so that the shutter speed control device 29 and the diaphragm control device 30 are omitted and the shutter speed or the diaphragm is adjusted manually in accordance with the exposure value displayed by the display device E. Further, it is possible to provide either only the shutter speed control device 29 or only the diaphragm control device J> 0 .

The following is the focus detection system 509841/0904

25U230

to determine the focusing of the imaging optics with the aid of the image sensor based on one shown in FIGS. 5 to 9 Embodiment explained, wherein the system is used in an ordinary camera.

Fig. 5 (a) shows the suitable for the in-focus detecting system image sensor, while Fig. 5 (b) a portion of the same magnification showing the image sensor IS of the representation is constructed in the drawing in such a manner ¹ in accordance with that "n" small light sensor elements P ₁ , P ₂ , P, .... P _ ₁ , P are arranged on the base plate G with the same dimensions in the form of a matrix.

The image sensor IS ¹ is arranged in a position equivalent to the film H relative to the image pickup optical system L of the camera, as shown schematically in Fig. 6 (a). HM is a small semitransparent mirror which is mounted obliquely on the optical axis of the image pickup optical system L between the image pickup optical system L and the film H, and which transmits the light beam to the central part of the object to be picked up through the image pickup optical system L. Light beam reflected so that it is projected onto the image sensor IS '. Consequently, as shown in FIG. 6 (b), the image sensor IS ¹ receives only the light beam at the central part H ^{1 a in the image plane H 1 of} the object to be recorded to be projected onto the film H.

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- 32 - 25U230

Pig. 7 shows the block diagram of the electrical circuit of an embodiment of the sharpening position determination system according to the invention, in which the image sensor IS 'shown in FIGS. 5 (a) and (b) is used, 101 being an X-coordinate shift register, which represents the "m" X coordinate axes X ₁ , X ₂ , ... X ^ ₁ , X _m , while 102 is a Y coordinate shift register which represents the ". £" Y coordinate axes Y ₁ , Y ₂ . .. Y _ ₁ , Y ^ represents (where Z is - n / m); a matrix is formed by these X and Y coordinate axes. The light sensor elements P ₁ , P ₂ , ... P- of the image sensor IS 'are arranged one after the other relative to the matrix such that they are connected by means of the two shift registers 101 and 102 for the X coordinates and the Y coordinates, respectively. 103 is a logarithmic amplifier for logarithmically compressing the output signal of each light sensor element P ₁ , P ₂ , ... P _n ; 104 is an analog-to-digital converter for converting an analog amount into a digital value; 105 and 106 are registers, while "107 is a zero detection circuit for the register 106. 108 is an arithmetic circuit for processing the absolute value of the difference between the output signals of the registers 105 and 106 by which, for example, the value!« - ß | assuming it is generated that the content of the register 106 is tx, while the content of the register 105 is β. 109 is an integrating circuit, 110 is a register and 111 is a comparison circuit for comparing the output signal of the register 110 with the output value of the integrating circuit 109, while 112 is a Drive source or a focus display device combined with it

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for the image pickup optical system. 113 is a control circuit for the central control of the circuits designated by the reference numerals 101, 104 to 106 and 108 to 110, respectively and fixtures.

The following is the operation of the focus detection system with the composition described above.

When the system is put into operation by turning on the power supply not shown in the drawing, the axes X ₁ and Y _{1 of} the shift registers 101 and 102, respectively, are first turned on, as a result of which the output signal of the light sensor element P ₁ at the coordinates (X ₁ , Y ₁ ) is input to the logarithmic amplifier 103. Then the analog output signal of the light sensor element P _{1, logarithmically compressed by means of the logarithmic amplifier 103, is converted into a digital value T 1} with the aid of the analog-digital converter 104, which is stored in the register 105. If another signal is stored in register 106 at this point in time, the absolute value of the difference between the signals stored in registers 105 and 106 is calculated immediately; However, since no signal has been stored in the register 106, the arithmetic circuit 108 is not put into operation by the control circuit 113 by means of a signal from the zero detector circuit 107. Thereafter, with the aid of a signal from the control circuit 113, the one stored in the register 105 is made

509841/0904

digital value r. of the output signal of the light sensor element P ₁ in the register 106, while the coordinate axis of the shift register 101 is shifted by one step in such a way that the X ^ axis is switched from the switched-on state to the switched-off state, while the Xp-axis is switched from the switched-off state in the switched-on state is switched, so that now the output signal of the light sensor element Pp arranged at the coordinates (Xp * ^ i ^ in the same way as with the light sensor element P ₁ via the logarithmic amplifier 103 and the analog-digital converter 104 as a digital value in is stored in the register 105. When signals are stored in both registers I05 and IO6, the control circuit 113 immediately starts the arithmetic circuit 108 in order to calculate the absolute value of the difference between the signals stored in the registers I05 and 106, namely (r., - r «|, the control circuit II3 sending the received digital value to the In integrating circuit 109 transfers while the signal stored in register 105 is transferred to register IO6. If the coordinate axis of the shift register 101 is then shifted by a further step by means of a signal from the control circuit 113, the output signal of the light sensor element P, at the coordinates (X- ,, Y ₁ ) is converted into an output signal r, by the same process as before. implemented and in the arithmetic circuit IO8 the value I r ₂ -r,) is calculated, which is then transferred to the integrating circuit 109 so that it becomes the previous value I r. - r " I is added. If after repeating the same process the shift becomes too

509841 / 09CU

of the coordinate axis X of the shift register 101 is completed (namely, when the output signal of the light sensor element P has been processed on the coordinates (X, Y ^)), the shift register 101 gives an output signal CA ₁ to the shift register 102 in such a manner that the coordinate axis of the shift register 102 is shifted in the same manner as that of the shift register 101. In this way, the output signal of the light sensor element P _{1n +} -! processed at the coordinates (X ₁ , Y ₂ ). When, after repeating the same process, the output _{signals up to the last light sensor element P at the coordinates (X m} , Yjg) have been processed, the shift register 102 outputs an output signal CA ₃ to the control circuit II3. The through the integrating

device 109 is the value calculated at this point in time, ρ 1 ¹ VI " ¹ Vl / namely the total sum of the absolute values of the differences between the output signals of each pair of light sensor elements P ₁ to P of the image sensor IS ¹ , the output signals being logarithmically compressed, amplified and Immediately after the receipt of the signal CAp from the shift register 102, the control circuit 113 causes the comparison circuit 111 to compare the value calculated by the integrating circuit 109 with the signal stored in the register 110 (which is zero at this point in time). After repeating the same operating process, the change in the value calculated by the integrating circuit IO9 is determined by scanning different image planes by means of the light sensor elements P ₁ , Pp, ·· ♦ P », namely while moving the value shown in FIG

509841/0904

optical image pickup system L from the focus setting for "infinity" to the focus setting for the smallest distance the signals are processed as described above, the value Σ calculated by the integrating circuit 109 changes at the same time as shown in FIG the value at the focus is greatest. This is due to the fact that the image of the object to be photographed on the image sensor IS 'becomes sharpest when the image pickup optical system L reaches the in-focus position, whereby the then existing difference between the output signals of two adjacent light sensor elements in the image sensor IS ¹ becomes greatest. That is, the value % increases as the image pickup optical system approaches the in-focus position, it is greatest when the system is in the in-focus position, and it decreases as the system moves away from the in-focus point. It is therefore possible to determine the focus point by successively comparing the value Σ calculated by the integrating circuit 109 with the next value Σ- with the aid of the comparison circuit, so as to determine the turning point of the curve shown in FIG.

When the first process from the output of the light sensor element P ^ to the output of the light sensor element P _{n has been} completed, the value calculated by the integrating circuit 109 is stored in the register 110. On the other hand, the X ₁ -AChSe of the shift register 101 and the Y ^ -axis of the shift register are at this point in time

509841/0904

102 is switched on, whereby the second process sequence from the output signal of the light sensor element P to the output signal of the light sensor element P begins with the aid of the signal from the control circuit 113. When the digital values of the output signals of the light sensor elements P ₁ , Pp >> · ♦ · P are r '^, r'p, ... r ¹ , the total sum of the values processed by the integrating circuit 109 can be similarly

η as has been completed in the previous case by be X_ l ^r 'ki ~ ^v \ ^ irückt ^of g ^{e (.} As soon as the second process with the aid of the integrating circuit 109, the control circuit 113' that the comparison circuit 111 to by the integrating circuit 109 calculated value (τ Ir 'ι "r'.l) with that in the

k = 2 ¹ ^ ^{1 K}

Register 110 compares stored value (^ - \ r. _ ^ - r I). At this time, if the value stored in the register 110 is smaller than the value calculated by the integrating circuit 109, namely, if Σ>, ir, ₁ - rj ^ ^ ² i ^r 'ki " ^r ' kJ, the same process is repeated , until the value stored in the register 110 becomes greater than the value calculated by the integrating circuit 109, the comparison circuit 111 then emitting a focus adjustment signal to the control circuit 113. By means of this signal, the control circuit 113 terminates the scanning of the image plane by means of the light sensor elements P ₁ , Pp,..

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In the present embodiment, the output signal is of each light sensor element of the image sensor IS. ' logarithmically compressed, amplified and then converted into a digital value; It goes without saying, however, that the output signal of each light sensor element can be converted directly into a digital fourth without it is logarithmically compressed and amplified. However, if the output of each light sensor element is logarithmic is compressed and amplified, the noise in the sampling signal can be kept as small as possible, even when the brightness of the object to be photographed changes during the scanning of the image pattern of the object to be photographed means the light sensor element'e changed to a certain extent, so that as a result, an erroneous puncture of the sharpness ellermittungsvorrichtung can be avoided.

As an image sensor for use in the focus determination system according to the invention, in addition to the image sensor with an arrangement pattern of the light sensor elements as shown in Fig. 5 (a) and (b), the image sensor IS with an arrangement pattern of the light sensor elements as shown in FIG. 1, with various variations the arrangement pattern of the light sensor elements are possible.

An embodiment of the focus detection system according to the invention is with her practical installation in an ordinary camera shown schematically in FIG. The camera in the drawing is a great

509841/0904

25U230

Conventional motion picture camera, only the essential parts are shown.

As shown in the drawing, the first lens group L ₂ and the second lens group L, the photo lens groups L ₂ , L, and L ₁ . commonly used as an objective lens for distance detection. The lens group L _{2 is held} by a lens frame 114 with a toothed rack 114a and is moved along its optical axis ^{with the aid of the revolutions of a motor 112a via a gearwheel 115 attached to the axis of rotation 112a 1 of the motor.} A light beam splitter 116, which has two semitransparent mirrors 116a and 116b, is arranged between the lens group L 1 and the lens group L 1. A lens group L ^, a mirror prism 117 and a lens group L, - form a viewfinder optical system. The semi-transparent mirror 116a is arranged obliquely to the optical axis so that the light beam coming from the lens group L to the film H is branched off to the viewfinder optical system. In the optical path from the mirror 116a to the viewfinder optical system, the second semitransparent mirror 116b is arranged so that the light beam is further branched off into an image forming lens 118.

The image sensor IS 'is disposed behind this image forming lens 118 and in a position equivalent to that of the film H _{relative to the lens groups L 2 and L.}

112b is the display device shown in optical image 509841/0904

.I ₁₀ . . 25U230

Sucherweg is arranged such that the display in the viewfinder of the camera can be read, while J is a circuit block comprising the elements indicated by 101 to 111 and 113 in FIGS contains; the display device 112b is connected to the output terminal of the circuit block together with the motor 112a J connected. Namely, the motor 112a and the display device 112b correspond to the block 112 in FIG. 7.

121 is a spring arranged between the lens barrel 114 and the camera body, by means of which the lens barrel 11 * 1 is forced to the right in the drawing, so that the lens group Lp.normally in the focus position held to be infinite distance.

119 and 120 are a shutter and a diaphragm in the conventional motion picture camera, while 122 is a two-stage release button which is so constructed that, at the first stage, the focus detection system is operated while at the second stage the shutter is operated.

When the motion picture camera with the structure described above is aimed at the desired subject and the release button is pressed to the first stage, the circuit block J is operated and the focus detection function of the image pickup optical system starts. In particular, the image pattern of the recording object is thereby used scanned by means of the image sensor IS ', with the output from the circuit block J as a result of the scanning signal

509841/0904

_ I ₁₁ _ 25U230

Output signal of the motor 112a runs in the direction of the arrow in the drawing, so that the lens group L _{2 is} moved forward against the force of the spring 121 from the focus position for an infinite distance in the direction of the arrow in the drawing. When the lens group Lp reaches the focusing position for the object to be photographed during the forward movement, the image of the photographed object on the image sensor IS ¹ becomes the sharpest, with the circuit block J immediately stopping the motor 112a by means of the scanning signal of the image sensor IS ^{1, so that the lens group Lp} in this in-focus position while the circuit block J simultaneously operates the display device 112b so as to indicate that the lens group Lp is in the in-focus position. In this state, the image of the object to be shot on the film H is sharpest.

Accordingly, when the release button 122 is pressed to the second stage in this state, the shutter becomes the shutter. 119 is actuated to expose the film H on which the sharpest image of the object to be recorded is obtained.

If the release button 122 is then released, the power supply to the circuit block J is interrupted, so that the lens group Lp by means of the spring 121 automatically is returned to the focus position for infinite distance.

With the focus determination 509841/0904 according to the invention

system, the image pattern of the object to be recorded is scanned in a purely electrical manner as described above, whereby the mechanical scanning device is unnecessary in the conventional system, so that according to the invention the focus detection device can be easily made compact, which is a small optical device how a camera, for example, is very beneficial. Furthermore, in the focus detection system according to the invention the output of each light sensor element is processed after conversion into a digital value, so that in comparison with the conventional analog value processing system, the electrical processing is remarkably simple, wherein at the same time, the accuracy of the focus point determination can be extremely increased compared to the conventional system can. Furthermore, in the focus determination system according to the invention, the image pattern of the object to be recorded can be scanned at a very high speed so that an accurate in-focus signal can be obtained.

It goes without saying that the drive source symbolically represented in FIG. 9 by the motor 112a for the automatic focus adjustment of the optical system can be omitted in that the focus adjustment of the optical System is performed manually using the focus point indicator.

Further, it is of course possible that the focus point detection device or the automatic

509841/0904

.I ₁₃ - 25H23Q

Focus adjustment device according to the invention both as a device in an optical device such as A camera can be built in as well as used as a stand-alone device along with the optical device can. In the case of an independent device, a distance measuring device is obtained in a simple manner if the focus point display device in the embodiment exchanged for a distance indicator.

Below is an embodiment of an invention ' according to the system for both exposure metering and for the focus determination using a common image sensor with reference to FIGS. 10 and 11 explained using the system applied to an ordinary camera.

Fig. 10 is a block diagram of the electrical circuit of one embodiment of the system operated by means of a common image sensor both an exposure measurement and a determination · of the focus point of the optical System can perform.

In the embodiment of the system shown in FIG. 10, not only the image sensor IS shown in FIG. 1 and the image sensor IS ^{1 shown in FIGS} Having arrangement pattern of the light sensor elements. However, the case is explained here in which the

509841/0904

in Pig. 1 shown image sensor IS is used.

In the drawing, 201 is a shift register, 202
an analog switch connected to each of the light sensor elements, 203 a logarithmic amplifier for logarithmic compression and amplification of the output signal of a
each light sensor element of the image sensor IS and 204
Analog-to-digital converter for converting each output signal of the logarithmic amplifier 2Q3 into a digital value, while 205 and 207 are registers and 206, 209, 212 and 213 are gates. 208 is a computing circuit for
Calculating the absolute value of the difference between the signal values stored in registers 205 and 207; 210 is an adding circuit for adding the value calculated by the arithmetic circuit 208 to that in a register 211
stored signal value; 21 ¹ I and 215 are registers; 216 is a comparison circuit for comparing the ^{signal value stored in the register 21 1} I with that in the register 215
stored signal value, while 217 is the drive source for the image pickup optical system and 217 ^{1 is} the focus point display device. 218 is a division circuit for dividing the signal value stored in the register 211, 219 is an arithmetic circuit for logarithmic
Compression, amplification and processing of the output signal of the division circuit 218 together with the digitally converted shutter speed value Tv or aperture value Av
and the pilm sensitivity value Sv for obtaining the exposure value, 220 is an aperture control device, 220 'is a

509841/09 (K

Shutter speed control device, 220 "is an exposure value display device, 221 is a control circuit for controlling the entire system, and 222 is a changeover switch for switching from one exposure control system to another exposure control system.

The image sensor IS is in the image formation position or in a position equivalent to the image formation position of the optical image recording system, not shown in the drawing, or in the image formation position of a optical image formation systems arranged for the image sensor IS.

In the above arrangement, the focus detection system consists of the image sensor IS and the Elements 201 to 208, 210, 211 and 213 to 216, while the exposure metering system consists of the image sensor IS and the elements 201st to 205, 209 to 212, 218 and 219.

The operation of the above-mentioned systems is explained below.

In order to determine the focus point of the optical system, the system shown in the drawing is used to start up the system current switch, not shown, closed, by means of the control signal generated by the control circuit 221 the gate circuits 206 and 213 are brought into the switched-on state (and thereby the gate circuits 209 and

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- 46 - 25H230

212 remain in the switched-off state), while the shift register 201 begins to act. In the analog switch 202 each of the light ens o-re learn nt e I ¹ , 2 ^f ,. ^{When the first switching element corresponding to the light sensor element I 1} in the analog switch 202 is actuated by means of the shift register 201, the output signal of the light sensor element 1 'is transmitted via the analog switch 202 to the logarithmic amplifier 203 so that it is logarithmically compressed The analog amount of the output signal of the light sensor element 1 * which is logarithmically compressed and amplified by means of the logarithmic amplifier 203 is converted by means of the analog-digital converter

204 converted to a digital value P ₁ and then in the register

205 saved. If a signal value were stored in register 207 at this point, the control circuit would 221 immediately emit a control signal to the arithmetic circuit 208, so that the arithmetic circuit 208 calculates the absolute value of the Difference between the signal values stored in the two registers 205 and 207 could calculate.

At this time, however, no signal value is stored in the register, so that the control circuit does not operate the arithmetic circuit 208. Polarity is achieved by means of the control signal generated by the control circuit 221 the signal value stored in * the register 205,

509841/0904

17 -

namely, the digital value of the logarithmically compressed and amplified output signal of the light sensor element I ^{1 is} stored in the register 207 via the gate circuit 206, while the shift register 201 is shifted by one level at the same time. In this way, the first switching element of the analog switch corresponding to the light sensor element 1 'is switched off, while the ^{second switching element corresponding to the light sensor element 2 1} is switched on, so that in the same way as the output signal of the light sensor element I ^1, the output signal of the light sensor ^{element 2 f is} processed and in is stored in register 205 as signal value p ~. When a signal value is stored in the register 207, the control circuit 221 outputs a control signal to the arithmetic circuit 208 so that the absolute value of the difference between the signal values stored in the registers 205 and 207 is calculated. Therefore, the value then calculated by the arithmetic circuit 208 can be expressed _{by Jp 1 - ppj.} The value calculated by the arithmetic circuit 208 is added to the signal value stored in the register 211 (the signal value stored in the register 211 being zero) by the adding circuit 210, and stored in the register 211 (so that the signal value stored in the register 211 at this time stored value is equal to Ip ₁ - P ₂ 1). Then, by means of the control signal from the control circuit 221, the signal value stored in the register 205 is stored in the register 207 via the gate circuit 206 (that is, the signal value p «des _{is used in the register 207 instead of the signal value P 1 of} the output signal of the light sensor generator I ¹ Output signal

509841/0904

--He- 25H230

nals of the light sensor element 2 '), in which case the shift register 201 is shifted by a further stage by means of the control signal generated by the control circuit 221 in ^{such a way that the output signal of the light sensor element 3 1} is the same as in the aforementioned two Cases is processed so that it is stored in the register 205 as a signal value p-. When a signal value is stored in the register 205, the control circuit 221 operates the arithmetic circuit 208 to perform the above process. _{In this way, the value Ip 2} -p, (which is calculated by the arithmetic circuit 208, is added to the existing value Jp ₁ -p ₂ } stored in the register 211 and is then stored in the register 211. Consequently, it is then in The value stored in the register 211 is equal to Jp ₁ - p "| +) P ₂ ~ Pz J · The same process is repeated until the output of the light sensor element n ^{1 has been} processed. After processing all output signals of the light sensor elements up to the light sensor element n ^f , the is in the register

211 stored value equal to "Σ. | P" PI »namely equal

k = 2 k-1 k

the total sum of the absolute values of the differences in the output signals between two adjacent light sensor elements of the image sensor IS, the output signal according to each light sensor element is logarithmically compressed and converted into a digital value. By means of the in the control circuit 221 generated control signal is the one at that time in the

η
Register 211 stored values ^ ₂ JP ₁ - ρ J immediately over

the gate circuit 213 is stored in the register 214. Of the

S09841 / 0904

The value stored in the register 214 is compared with the signal value stored in the register 215 by means of the comparison circuit 216. The value stored in register 215 at this point in time is equal to zero, while the value ^ ₂ IPir-1 ~ ^ k ^ 6 ^{r is} greater than zero, so that the value stored in register 214 is greater than that in the Register 215 stored value.

In this way, by scanning the image plane by means of the light sensor elements 1 ', 2',. Namely, if the signals are processed as described above while the image forming optical system not shown in the drawing for the image sensor IS is moved, for example, from the focus point for infinite distance to the focus point for the shortest distance, the calculated by the addition circuit 210 and changes value 2 stored in register 214! as shown in Fig. 8 in the same manner as in the focus detection system shown in Fig. 7, the value becoming the largest at the time of focus. Ie the value Σ. increases as the imaging optical system approaches the in-focus position, is greatest when the imaging optical system is in the in-focus position, and decreases when the imaging optical system is out of focus.

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position removed. Thus, by successively comparing the value Σ- calculated by the adding circuit 210 and ^{stored in the register 21 1} J with the next value Σ, it is possible to obtain the focus point when the maximum value of Σ. , namely the reversal point of the curve shown in FIG. 8 is determined.

Because the first time the image of the

object to be recorded by means of the light sensor elements I ¹ , 2 ',

η ... η 'obtained sampling signal, namely 2; _o Ip ₁ , - - p. I is greater than the value stored in the register 215 at that time, the control circuit 221 generates a control signal so that the value stored in the register 214 is transferred to the register 215 while the shift register 201 is reset in the manner that the second scanning of the image of the object to be photographed is started by moving the optical image formation system, not shown in the drawing. Therefore, if the digital values of the output ^{signals of the light sensor elements are p 1} - ,, p'pj ··· P ¹ , as in the previous case, the total sum of the values calculated by the adding circuit 210 and ^{stored in the register 21 1} I can be given by η

J ^ r ₂ 'ρ'ir-i ~ ^p ' k ' ^{from being} pressed. As soon as a new signal ^{value is stored in the register 21 1} I, the control circuit 221 sets the comparison circuit 2l6 in operation in order to compare the signal value stored in the register 214 with the signal value stored in the register 215, with the scanning of the image of the object to be recorded

509841/0904

continued if the value stored in register 214 is greater than that in register 215 at this point in time

η stored value (namely in this case ^ - Jp *. "j - Ρ'τ, Ι /"

21 j ρ - ρ j) until the one stored in register 214 Value is less than the value stored in register 215

η η

(namely ^ ₂ Ip ¹ ^ ₁ - P 'J ^- ^ jJ ₂ t ^p kl " ¹ V ⁾ * ^{where ZU}

At this point in time, the comparison circuit 216 outputs a signal to the control circuit 221. The fact that the value stored in register 214 becomes smaller than the value stored in register 215 means that the value Σ calculated by addition circuit 210 and stored in register 214 is the maximum, namely the highest point in the in Fig. 8 reached curve shown, that is, that the optical image pickup system not shown in the drawing reaches the focus point. Thus, the signal generated by the comparison circuit 216 is the focus signal. By means of this focusing signal, the control circuit 221 immediately terminates the scanning of the image of the object to be recorded by means of the light sensor elements 1 ', 2 ¹ , ... n ¹ , while at the same time it outputs a control signal to the drive source 217 of the optical image recording system and to the focus display device 217', to stop the drive device of the image pickup optical system and to indicate that the in-focus position has been reached.

The drive source 217 can be omitted if the focusing position of the optical image pickup

5Q9841 / 0904

systems by manually setting the optical image recording system is achieved by means of the in-focus point indicator 217 '.

The light metering operation is explained below. When the focusing of the image pickup optical system has been completed, the control circuit 221 generates a control signal so that the gate circuits 206 and 213 are switched from the on-state to the off-state, while the gates 209 and 212 are switched from the off-state to the switched on state. If the control signal is transmitted from the control circuit 221 to the shift register 201 in this switching state, the shift register 201 brings the ^{first switching element of the analog switch 202 corresponding to the light sensor element I 1} into the switched-on state, so that the output signal of the light sensor element I ^{1 is sent} to the logarithmic amplifier 203 is output, which logarithmically compresses and amplifies the output signal of the light sensor element I ^1. The logarithmically compressed and amplified output signal of the light sensor element I ¹ is converted into a digital value by means of the analog-digital converter 20 * 1 and stored in the register 205. Then, by means of the control signal generated by the control circuit 221, the signal value of the output signal of the light sensor element 1 ′ stored in the register 205 is transferred to the register via the gate circuit 209 and the adding circuit 210.

809841/0904

When the signal value stored in the register 205 is transferred to the register 211, the control circuit 221 outputs a control signal to the shift register 201 which brings the second switching element of the analog switch 202 corresponding to the light sensor element 2 'into the switched-on state, so that the output signal of the Light sensor element 2 ^f is output to the logarithmic amplifier 203, the output signal of the light sensor element 2 'being stored in the register 205 in the same way as in the case of the light sensor element 1' and output via the gate circuit 209 to the adding circuit 210. After it has been added to the signal value of the output signal of the light sensor element I ¹ stored in the register 211, the signal value of the light sensor element 2 ′ output to the adding circuit 210 is again stored in the register 211. The same process is then repeated up to the light sensor element n ¹ , whereby the total sum of the signal values of the output signals of the light sensor elements 1 'to n ^{1 is} stored in the register 211. When the total sum of the signal values of the output ^{signals of the light sensor elements 1 'to n 1 has} been stored in the register 211, the control circuit 221 outputs a control signal to the shift register 201 to shut it down and transfers the total sum of the signal values of the output signals of the stored in the register 211 Light sensor elements I ¹ to n ¹ to the division circuit 218. Since the division circuit 218 has been programmed in advance so that the value stored in the register 211 by the total number (n ^f ) of the light sensor

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■ - 5U -. 25U230

elements is divided, the signal value stored in the register 211 is divided by the total number (n ¹ ) of the light sensor elements and supplied to the arithmetic circuit 219 as the light measurement value of the object to be recorded.

At this point in time, on the other hand, according to the exposure control system selected by means of the switch 222, namely, depending on whether the diaphragm are automatically controlled by means of the diaphragm control device 220 or the shutter speed is to be automatically controlled by the shutter speed control circuit 220 ', which is logarithmic Compressed, amplified and converted into a digital value shutter speed value Tv or the logarithmically compressed, amplified aperture value Av converted into a digital value together with the likewise logarithmically compressed, amplified and the film speed value Sv converted into a digital value are supplied to the arithmetic circuit 219 so that the Computing circuit 219 the above-mentioned light measurement value of the object to be recorded together with the shutter speed value Tv and the film speed value Sv or processed together with the aperture value Av and the film speed value Sv to generate the exposure value. Depending on the switching status of the changeover switch 222, the exposure value is input to either the aperture control device 220 or the shutter speed control device 220 'is entered so that the aperture or shutter speed is automatically controlled during each existing exposure value, namely the aperture value or the Shutter speed value indicated by means of the display device 220 "

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will show. This ends the entire exposure measurement process,

11 schematically shows an embodiment of the system according to the invention for measuring the exposure and for determining the focus point by means of a common image sensor when it is installed in a conventional camera. In the drawing, L _{7 is} an image pickup optical system which is held in a lens barrel 223 and which is movable along its optical axis, being pulled to the right by means of a spring 224 attached between the lens barrel 223 and the camera body as shown in the drawing, so as to normally assume the focus position for infinite distance by the action of the spring.

A rack 223a is attached to a portion of the lens barrel 223 so as to mesh with a _{gear 227 attached to the output shaft 217a of the drive source 217 of the image pickup optical system L 7,} the drive source 217 being shown as a motor in the drawing.

Lg is an additional optical image formation system for measuring the light and the distance, which is held by means of a lens mount 225, which is connected via a connecting member 226 to the _{lens mount 223 holding the optical image recording system L 7} , the optical image formation system Lg in functional coupling with the optical image recording system along its optical

B09841 / 0904

Axis is movable. Said image sensor IS is installed in the optical path of the image formation optical system Lo,

228 is a conventional lamellar diaphragm mounted in said lens mount 223, through which, with the aid of of said aperture control device 220, the opening diameter is controlled. The functional relationship is in of the drawing shown schematically by the dashed line 228 '.

229 is the functional part of a conventional focal plane shutter, its puncturing speed is controlled by the aforementioned shutter time controller 220 ' will. The functional relationship is shown schematically in the drawing by the dashed line 229 '.

230 is a film, 231 is the swing mirror of the conventional single lens reflex camera, M is the circuit block with circuits 201 to 216, 218, 219 and 221 of Figs. and 232 is a two-stage release button constructed in this way is that in the first stage the circuit block M is put into operation, while in the second stage the oscillating mirror and the shutter operated.

The aforesaid focus position display device 217 'and the aforesaid exposure value display device 220 "are mounted in the optical path of the viewfinder as shown in the drawing so that

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the advertisements can be seen in the viewfinder.

The operation of the camera described above will be explained below. When the camera points to what you want The subject is directed and the release button 232 is pressed to the first stage, the circuit block becomes M put into operation so as to both the focus detection process of the image pickup optical system as well as the above-described exposure metering operation.

First, the image of the object to be photographed is scanned by means of the image sensor IS, which is formed by the optical imaging system Ln, and then the motor 217 starts to rotate in the direction of the arrow in the drawing in the direction of the arrow in the drawing, so that the optical Image recording system L _{7 is moved} in the direction of the arrow in the drawing, from the focussing point for the distance "infinite" against the force of the spring 22 ¹ I. At the same time calibration moved in functional coupling with the image pickup optical system L _7, the image formation optical system Ln in the direction of the arrow in the drawing, wherein during the feed operation of the optical systems L ₇ and L "upon reaching the focus of the object to by the two optical systems L ₇ and Lo is the sharpest image of the object to be recorded, which is formed on the image sensor IS by means of the optical system Lg, so that the circuit block M immediately drives the motor 217 by means of the scanning signal of the image at that time.

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sensors IS stops and in this way holds the two optical systems L ₇ and Ln in the in-focus position, the circuit block M at the same time actuating the focus display device 217 'to indicate that the image pick-up optical system L ₇ has reached the in-focus position. In this state, the image of the object to be photographed is sharpest on the film 230.

As soon as the focusing operation of the image pickup optical system L _{7 is} finished, the system initiates the exposure metering operation. The type of exposure control is determined by the selected switching state of the switch 222. Namely, when the changeover switch 222 is switched to the diaphragm control circuit 222, the diaphragm is automatically controlled with priority of the shutter speed, while when the changeover switch 222 is connected to the shutter speed controller 220 ', the shutter speed is automatically controlled with the priority of the diaphragm. (In the state shown in the drawing, the iris is controlled automatically.)

Consequently, at the time of exposure measurement, the photographer must determine the type of exposure control by means of the Determine switch, which in advance in the circuit block M the film speed value Sv and when desired automatic aperture control has to input the shutter speed value Tv, while it is desired when automatic shutter speed control must enter the film speed value Sv and the aperture value Av. (Consequently, the one in the The state of the shutter speed Tv shown in the drawing

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to be determined in advance.)

By means of the operating procedures described above, the system calculates the for the conditions in the Exposure value suitable for the image recording field from the value of the light measured in the image recording field of the image sensor IS, the film speed value Sv and the shutter speed value Tv or the aperture value Av, namely from the shutter speed value in the case of automatic aperture control and from the aperture value in the case of automatic shutter speed control, so that the exposure value is displayed by the display device 220 ", in the case of the automatic shutter speed control the operating speed of the operating parts 229 is automatically controlled by means of the control device 290 ' is, while in the case of the automatic diaphragm control, the opening diameter of the louver 228 by means of the control device 220 is controlled automatically. In this way the automatic control is for the prevailing conditions completed exposure suitable in the image pickup field.

If the release button is pressed down to the second stage in this operating state, the oscillating mirror becomes 231 pivoted out of the optical image recording path, while the shutter is operated so that the film 230 is in proper focus and exposure is exposed.

When the release button 232 is in the initial position 509841/09 (K

returns, the power supply to the circuit block M is interrupted so that the optical image recording system L ₇ automatically returns to the focusing position for the distance "infinite" by means of the force of the spring 224.

According to the above description, in the system according to the invention for focusing determination and for Exposure measurement with the aid of a common image sensor, the light sensor device used jointly for determining the focus and for exposure measurement from a number small light sensor elements, the output signal of each light sensor element after its conversion into a Digital value is processed, so that the electrical processing or calculation compared to the conventional The system in which the signal is processed as an analog amount is remarkably simple, whereby the signal processing circuit is remarkably simplified, the signal flow is controlled with great consistency, so that it is possible to to keep the measurement error in signal processing as small as possible. In particular, in the system according to the invention the entire signal processing is controlled in a digital way, so that the control of the signal processing is significantly simplified thereby making it possible to use a large number of light sensor elements in the light sensor device and thereby obtain a more accurate measurement.

In the invention it is of course possible to adjust the aperture diameter or the shutter speed in accordance with

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mung with the means of the display device !; 220 "displayed Manually controlling the exposure value when the aperture control device 220 and the shutter speed control device 220 can be omitted or only one of the control devices 220 or 220 'is provided.

It is also possible to use the drive source 217 for the automatic focusing device; of the optical System to be omitted and by means of the display device 217 'the focusing position of the optical image recording system set by hand.

The invention provides a system for exposure measurement and / or focus determination by means of an image sensor such as for example a photodiode array (MOS image sensor), charge coupled divices (CCD) or the like with a large number of distributed or integrated created small light sensor elements, in which the image pattern of the object in a purely electrical manner in such a way is scanned that for processing one after the other the output signal obtained in each case of each light sensor element is converted into a digital value.

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Claims (1)

Claims ¹ Iy camera in which by processing a light beam converted into an electrical signal, at least either the exposure value can be determined or the focus setting state of the optical image recording system can be determined, characterized by a photoelectric conversion device (IS; IS ¹ ) which has a number of arranged or integrated small photoelectric conversion elements (I ¹ to n ¹ ; D ₁ to D; P ₁ to P) for converting the light beam into an electrical signal and which in a Position is arranged at which the light beam coming from the object to be recorded forms an image via an optical image recording system (L ₁ ; L2; L,) or another optical image formation system (Lg), a signal timing device (1, 2, 3, 5; 101, 102, 113; 201, 202, 221) for sequential output the output signals of the photoelectric conversion elements in the photoelectric conversion device, a signal digitizing device (B; 10 ¹ I; 20 ¹ I) for successively converting the output signals output successively by the photoelectric conversion elements by means of the signal timing device into digital values and at least either a first processing device (C; D; 210, 218; 219) for processing the in digital Values of converted output signals of the photoelectric conversion elements according to a certain predetermined appraisal 509841/0904 25U230 function to determine the exposure value or a second Processing device (108, 111; 208, 210, 216) for processing the output signals converted into digital values of the photoelectric conversion elements according to a certain predetermined estimation function to determine the Focus point of the optical system, whereby either a light metering signal or a focus point detection signal can be obtained. 2. A camera according to claim 1, characterized in that ^it comprises a first display device (E; 220 ") for displaying the measured exposure value in accordance with the processed by the first processing device output signal when the first processing device is provided, while ^s ^ ^e a second Display device (112; 112b; 217 ') for displaying the focus state of the optical system in accordance with the output signal processed with the aid of the second processing device, if the second processing device is provided. 3. Camera according to claim 2, characterized in that the first and the second display device in one Position are arranged at which the display can be seen in the field of view of the viewfinder of the camera. H. Camera according to one of claims 1 to 3, characterized in that it has an automatic exposure 509841 / Ό904 -64. 25H230 setting device (29, 30; 220, 22O ¹ ) for setting the exposure value in accordance with the output signal processed with the aid of the first processing device, if the first processing device is provided, while it has an automatic focus point setting device (112; 112a; 217) for setting the focus point of the optical system in accordance with the output signal processed with the aid of the second processing device, if the second processing device is provided. 5 ". Camera according to one of Claims 1 to k>, characterized in that the first processing device (C; D ;, 210, 218; 219) sums the digital values corresponding to the output signals of the photoelectric conversion elements, the total summed value by the number of Dividing elements and processing the value thus divided with the film speed converted to a digital value and either the shutter speed value converted to a digital value or the aperture value converted to a digital value, so as to determine the aperture value if the shutter speed value was processed or the shutter speed value to determine if the aperture value was used for processing. 6. Camera according to one of claims 1 to 5, characterized in that according to the by a programming device (H, 5, Rß> R ^ to R (-) for setting at least one optional light scanning area in the photoelectric 509841 / 09CU 25H230 Conversion device set state, the first processing device converts the output signal into a digital value of each photoelectric conversion element in the set light scanning area according to a certain predetermined one Puncture processed to determine the exposure value. 7. A camera according to claim 6, characterized in that the programming device at least one of the whole Light sensing surface of the photoelectric conversion device or may define another optional light sensing surface that is smaller than the total light scanning area. 8. Camera according to claim 7, characterized in that the first processing device the exposure value selecting either the value processed for the entire light-sensing area or that for another optional light-sensing area corresponding to the difference between the value processed for the entire light scanning area and calculated from the value processed for the other optional light scanning surface when using the programming device for at the same time both the entire light-scanning area and another optional light-scanning area are set, which is smaller than the total light scanning area. 9. Camera according to claim 7 or 8, characterized in that the first processing device has a processing circuit (D) for adding up the converted into digital values Output signals of all photoelectric conversion elements in the 509841/0904 photoelectric conversion device and for dividing the added value by the number of elements. 10. Camera according to one of claims 7 to 9 »characterized in that the first processing device a processing circuit (C) which is used to add up the output signals converted into digital values of the photoelectric conversion elements located in a light scanning area smaller than the whole Light-sensing area, and for dividing the added value by the number of those located in the smaller light-sensing area Light conversion elements is used. 11. Camera according to one of claims 1 to 10, characterized in that the second processing device the absolute values of the differences between the digitally converted output signals of neighboring photoelectric signals Conversion elements in the photoelectric conversion device summarized to so from the summarized Value to determine the focus point of the optical system. 12. Camera according to one of claims 1 to 11, characterized in that the photoelectric conversion device is arranged in a position in which the device passes the light beam from the entire image area the camera receives the scene to be recorded. 13. Camera according to one of claims 1 to 10 and 12, 509841/0904 25U230 characterized in that the photoelectric conversion device to a prism surface (36a) formed as a semitransparent surface of a part of the optical viewfinder system the pentagonal roof prism (36) forming the camera is glued or opposed to the prism surface (36a) is arranged if the camera has only the first processing device. 1 * 1. Camera according to one of Claims 1 to 12, characterized in that the photoelectric conversion device is in the target image formation plane of the image pickup optical system or is arranged in a position which is optically equivalent to the target image formation plane. 15. Camera according to one of claims 1 to 12, characterized in that a further optical image formation system (Lg) in operational coupling to the optical Bildaufnahmesystein is provided. 16. Camera according to claim 15, characterized in that the photoelectric conversion device in the target image formation plane of the further image forming optical system or is arranged in a position corresponding to the Target image formation plane is optically equivalent. 17. Camera according to one of claims 1 to l6, characterized in that the photoelectric conversion device is an image sensor that has a number of small 509 8-4 1/0904 Having photodiodes or phototransistors in a are arranged or integrated on the same level. 509841/09 (K